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Training is an essential component of onboarding new hires in forensic science service provider (FSSP) laboratories. There are several DNA training standards published by the American Academy of Forensic Sciences (AAFS) Academy Standards Board (ASB) American National Standards Institute (ANSI) accredited framework. In this study, we conducted a survey of forensic DNA laboratory training programs to better understand training activities and materials. The survey was approved by the IRB and emailed to forensic laboratory directors, assistant directors, and/or DNA technical leaders and responses were submitted by them or their designees. Over thirty leaders and stakeholders responded. In this article, we report on the results of the survey. Respondents indicated that training activities included readings, writing assignments and quizzes, shadowing analysts, and mock casework and that training is documented and is a collaborative effort of the technical leader, unit supervisor, advanced forensic scientists, and other analysts and technicians. Laboratories assess competency using multiple methods including performance on mock casework, report writing, laboratory practical and competency tests, and a mock trial and testimony. The top three training activities reported are hands‐on practice, shadowing, and readings. The top three focuses of the training are laboratory techniques (extraction, quantitation, amplification, and capillary electrophoresis), STR typing, and mixture analysis. Ethics violations and failure to pass the competency tests and mock trial, even after remediation, are the top reasons new hires fail training. Finally, the top items respondents would like to spend more time offering training on are troubleshooting, validation, and root cause analysis. [ABSTRACT FROM AUTHOR]

Advancements in forensic DNA typing technology and methods have increased sensitivity and, while beneficial, carry the weight of more challenging profile interpretation. In response, the forensic DNA community has often requested more complex reference materials to address commonly encountered measurement and interpretation issues such as complex DNA mixtures, DNA degradation, and PCR inhibition. The National Institute of Standards and Technology (NIST) released Research Grade Test Material 10235: Forensic DNA Typing Resource Samples to support the forensic DNA community. Components include three single source samples, two degraded samples, and three mixture samples. As part of the Research Grade Test Material (RGTM) process, automated methods for bottling, alternative sample tube types, and the addition of carrier RNA for stabilizing low‐quantity samples were investigated. Both internal and external testing demonstrate the stability of the material over time at 4°C through qPCR testing. In the development of a data portal, users have been allowed to anonymously upload results and compare their data with NIST and others. This report describes the preparation and stability of this material. [ABSTRACT FROM AUTHOR]

Genetic assessment of highly incinerated and/or degraded human skeletal material is a persistent challenge in forensic DNA analysis, including identifying victims of mass disasters. Few studies have investigated the impact of thermal degradation on whole‐genome single‐nucleotide polymorphism (SNP) quality and quantity using next‐generation sequencing (NGS). We present whole‐genome SNP data obtained from the bones and teeth of 27 fire victims using two DNA extraction techniques. Extracts were converted to double‐stranded DNA libraries then enriched for whole‐genome SNPs using unpublished biotinylated RNA baits and sequenced on an Illumina NextSeq 550 platform. Raw reads were processed using the EAGER (Efficient Ancient Genome Reconstruction) pipeline, and the SNPs filtered and called using FreeBayes and GATK (v. 3.8). Mixed‐effects modeling of the data suggest that SNP variability and preservation is predominantly determined by skeletal element and burn category, and not by extraction type. Whole‐genome SNP data suggest that selecting long bones, hand and foot bones, and teeth subjected to temperatures <350°C are the most likely sources for higher genomic DNA yields. Furthermore, we observed an inverse correlation between the number of captured SNPs and the extent to which samples were burned, as well as a significant decrease in the total number of SNPs measured for samples subjected to temperatures >350°C. Our data complement previous analyses of burned human remains that compare extraction methods for downstream forensic applications and support the idea of adopting a modified Dabney extraction technique when traditional forensic methods fail to produce DNA yields sufficient for genetic identification. [ABSTRACT FROM AUTHOR]

There is interest in comparing the output, principally the likelihood ratio, from the two probabilistic genotyping software EuroForMix (EFM) and STRmix™. Many of these comparison studies are descriptive and make little or no effort to diagnose the cause of difference. There are fundamental differences between EFM and STRmix™ that are causative of the largest set of likelihood ratio differences. This set of differences is for false donors where there are many instances of LRs just above or below 1 for EFM that give much lower LRs in STRmix™. This is caused by the separate estimation of parameters such as allele height variance and mixture proportion using MLE under Hp and Ha for EFM. This can result in very different estimations of these parameters under Hp and Ha. It results in a departure from calibration for EFM in the region of LRs just above and below 1. [ABSTRACT FROM AUTHOR]

Crime laboratories have been faced with large casework backlogs due to lengthy processing times, limited resources and scientists, and rising crime rates. Evidence related to sexual assault crimes, specifically sexual assault kits (SAKs), heavily contribute to the reported backlogs. Although more sensitive, faster chemistries and automated techniques have been implemented over the years, the traditional STR workflow remains relatively unchanged. Enhanced workflows such as direct PCR and Rapid DNA have the potential to streamline the processing of forensic evidence items including those commonly submitted in SAKs, but the FBI QAS guidelines restrict CODIS‐approved labs from implementing these methods for forensic samples. Recent studies have shown decreased turnaround times and improved or comparable profiling success with both approaches. However, review of the literature shows a lack of in‐depth research comparing traditional DNA workflows to faster and more sensitive direct PCR and/or Rapid DNA approaches for evidentiary samples, especially for SAKs. By providing the forensic science and criminal justice communities with the strengths and limitations of direct PCR and Rapid DNA methods, stakeholders and policy makers may be better informed. [ABSTRACT FROM AUTHOR]

Interpreting forensic DNA signal is arduous since the total intensity is a cacophony of signal from noise, artifact, and allele from an unknown number of contributors (NOC). An alternate to traditional bulk‐processing pipelines is a single‐cell one, where the sample is collected, and each cell is sequestered resulting in n single‐source, single‐cell EPGs (scEPG) that must be interpreted using applicable strategies. As with all forensic DNA interpretation strategies, high quality electropherograms are required; thus, to enhance the credibility of single‐cell forensics, it is necessary to produce an efficient direct‐to‐PCR treatment that is compatible with prevailing downstream laboratory processes. We incorporated the semi‐automated micro‐fluidic DEPArray™ technology into the single‐cell laboratory and optimized its implementation by testing the effects of four laboratory treatments on single‐cell profiles. We focused on testing effects of phosphate buffer saline (PBS) since it is an important reagent that mitigates cell rupture but is also a PCR inhibitor. Specifically, we explored the effect of decreasing PBS concentrations on five electropherogram‐quality metrics from 241 leukocytes: profile drop‐out, allele drop‐out, allele peak heights, peak height ratios, and scEPG sloping. In an effort to improve reagent use, we also assessed two concentrations of proteinase K. The results indicate that decreasing PBS concentrations to 0.5X or 0.25X improves scEPG quality, while modest modifications to proteinase K concentrations did not significantly impact it. We, therefore, conclude that a lower than recommended proteinase K concentration coupled with a lower than recommended PBS concentration results in enhanced scEPGs within the semi‐automated single‐cell pipeline. [ABSTRACT FROM AUTHOR]

An increasing number of US jurisdictions have begun to submit their previously untested sexual assault kits (SAKs) for DNA testing. However, best practices for what should happen after testing are not well established. Should all cases be investigated regardless of the testing outcome or only those that returned a DNA hit? We examine an early‐adopter jurisdiction that has completed testing and investigating all 5165 previously never tested kits. We explore and compare the criminal justice outcomes and cost‐effectiveness of investigating: all cases, those with CODIS hits, and those without CODIS hits. Findings indicate the SAK initiative produced a cost savings to the community: $26.48 million ($5127 p/kit) after the inclusion of tangible and intangible costs of future sexual assaults averted through convictions, of which $9.99 million ($1934 p/kit) was from also investigating no CODIS hit cases. When considering only the costs to law enforcement, investigating all cases cost $12,000 p/additional conviction. Findings also illustrate the cost‐effectiveness of investigating no CODIS hits cases and support an "investigate all" approach. This study enhances our understanding of the economic value of what comes after testing kits and investigating cases and provides a framework for jurisdictions for prioritizing resources and maximizing outcomes from testing. [ABSTRACT FROM AUTHOR]

The use of a fluorescent dye to visualize cellular material on surfaces offers a targeted sampling approach for locating touch DNA on casework items. However, the current application of such dye is not feasible for examination of relatively large items. As a result, development of an efficient dye application system is required to translate this approach into practice. Here, the spray pattern (area covered, intensity, and evenness) of 15 different commercial spray devices was examined visually using food coloring. From this, five devices were selected to apply Diamond Nucleic Acid Dye (DD) to three substrates (glass slide, plastic sheet, and brown packing tape) seeded with saliva and touch DNA. The cellular material was visualized using the Dino‐lite Microscope and Polilight. The inhibitory effects of DD afforded by each spray device were examined using Identifiler Plus® DNA profiling kit and a DNA input of 800 pg. The two most promising devices were further tested on a range of mock casework items seeded with touch DNA. The results presented demonstrate the feasibility of a spray system to apply DD to large surfaces and subsequently detect cellular material at both micro and macroscale. Specifically, the data suggest that a pressurized continuous‐spray system is favorable and that droplet size influences the intensity of fluorescence and surface coverage. Furthermore, this study indicates that full STR profiles can be obtained following spraying with DD solution, even with excessive application, which is essential for the widespread use of these devices in casework. [ABSTRACT FROM AUTHOR]

The probabilistic genotyping software Forensic Statistical Tool implements a semi‐continuous model for DNA interpretation. This software omits any locus where the sum of the allele probabilities equals or exceeds.97. There has been criticism that this function is neither signaled by the software nor disclosed in publications. We investigate the effect of this function by creating a near clone of the model and applying it to five‐ and six‐allele loci for three‐person mixtures created in the expected population proportions. On average, the dropping of a locus is conservative for six‐peak loci and nonconservative for five‐peak loci. For persons of interest (POIs) with rare alleles, the dropping is usually conservative. For POIs with common alleles, the dropping of the locus is often nonconservative. This article is categorized under:Forensic Biology > Interpretation of Biological EvidenceForensic Biology > Forensic DNA TechnologiesJurisprudence and Regulatory Oversight > Expert Evidence and Narrative [ABSTRACT FROM AUTHOR]

There are three possible outcomes from drug therapy: the drug performs as intended; the drug has no effect; or the drug causes an adverse reaction. Variation in drug and endogenous toxin metabolism among individuals in part can be due to genetic makeup. The goal of pharmacogenetics is to elucidate the genetic variation contributing to absorption, distribution, metabolism, excretion, and response (ADME‐R) so that adverse drug reactions can be avoided, and to characterize differential enzyme activity informing appropriate drug dosage on the individual and population levels. The postmortem molecular autopsy may use pharmacogenetic information from a decedent to make conclusions about cause (CoD) and/or manner of death (MoD) when traditional medico‐legal autopsies are negative. The cytochrome p450 family is a group of pharmacogenetically relevant targets with demonstrable utility in the postmortem setting and several key historical applications. ATP‐binding cassettes and opioid receptors are additional critical drug response proteins with essential rolls in additive and suicidal behaviors and drug overdose. Historically, the discipline relied on genetic variation with large effects on a broad spectrum of endogenous and foreign compounds. However, recent advances in pharmacogenomics highlight rare variants and noncoding variation as strong contributing factors to the accuracy of drug response prediction. Furthermore, there is a push to develop more comprehensive predictive models incorporating both rare and common variants contributing to drug response. These advanced genetic capabilities will enable more accurate predictions of drug‐related CoD and/or MoD determinations and contribute to the growing overlap between medical and forensic genetics. This article is categorized under: Forensic Biology > Forensic DNA TechnologiesToxicology > OpioidsForensic Medicine > Methods for Certification of Cause and Manner of Death [ABSTRACT FROM AUTHOR]

As DNA technology becomes increasingly sensitive, forensic laboratories are receiving more low‐template DNA samples. These samples, already low in DNA content, become even more challenging to process as the available DNA becomes further reduced during the extraction step. In this study, two extraction modifications were tested to determine if the cause of DNA loss could be identified and mitigated. A double lysis technique was used to test for DNA loss in the sample collection substrate, and lysate eluates were re‐extracted to determine DNA loss from inefficient binding to the silica column. Both modifications showed DNA was lost at these steps. However, resulting STR profiles from these samples had fewer peaks and lower peak heights when compared to samples processed with no extraction modifications. Overall, the potential benefits of adding these extraction modifications for low‐template DNA sample processing are not enough to justify the risk associated with additional manipulation. [ABSTRACT FROM AUTHOR]

Insects have historically been used in criminal investigations to provide information in relation to postmortem intervals (PMIs) but the field of forensic entomology is expanding. It is now recognized that insects can act as vectors of human and mammalian DNA through the consumption of biological material, with extraneous DNA able to be extracted and genotyped from all stages of the life cycle, and insect feces and regurgitant (artifacts). To date, DNA recovered from insects have been used to inform investigations into neglect and homicide, link body parts, and to identify victims of crime. It may also potentially be used to identify assailants, confirm the food source of insects to determine their relevance in PMI calculations, determine if a crime has occurred, identify scenes of crimes, and link people to locations and other individuals. However, insects which have consumed biological material may also transfer DNA by traveling to new areas, or depositing it via their artifacts, either within crime scenes or laboratories, or at locations distant to the food source. This could contaminate forensic evidence, confound investigations, and/or falsely incriminate or exclude an individual. Therefore, it is important that there is increased awareness into both the utility of insects as vectors of forensically relevant DNA, and the potential for contamination. This article is categorized under:Forensic Biology > Forensic DNA TechnologiesForensic Science in Action/Crime Scene Investigation > Crime Scene ExaminationForensic Biology > Interpretation of Biological EvidenceForensic Biology > Body Fluid Identification [ABSTRACT FROM AUTHOR]

As DNA technology becomes increasingly sensitive, forensic laboratories are receiving more low‐template DNA samples. These samples, already low in DNA content, become even more challenging to process as the available DNA becomes further reduced during the extraction step. In this study, two extraction modifications were tested to determine if the cause of DNA loss could be identified and mitigated. A double lysis technique was used to test for DNA loss in the sample collection substrate, and lysate eluates were re‐extracted to determine DNA loss from inefficient binding to the silica column. Both modifications showed DNA was lost at these steps. However, resulting STR profiles from these samples had fewer peaks and lower peak heights when compared to samples processed with no extraction modifications. Overall, the potential benefits of adding these extraction modifications for low‐template DNA sample processing are not enough to justify the risk associated with additional manipulation. [ABSTRACT FROM AUTHOR]

In this study, we sought to document the efficiency of primer extension capture (PEC) as a method to enrich DNA eluates of targeted DNA molecules and remove nontarget molecules from pools containing both. Efficiency of the method was estimated by comparing number of "copies in" to "copies out" by quantitative polymerase chain reaction. PEC retention of DNA targets ranging 109‐288 base pairs (bps) in length was 15.88–2.14% (i.e., loss of 84.12–97.86% of target molecules). Experimental modifications of the PEC method resulted in no significant improvements. However, the benefit of PEC was revealed in its ability to remove most nontarget DNA molecules (99.99%). We also discovered that many (56.69%) of the target molecules are "lost" prior to their immobilization on the streptavidin‐coated beads. These estimates of methodological efficiency are directly comparable to previous ones observed following "fishing" for DNA, an alternative method for DNA enrichment. [ABSTRACT FROM AUTHOR]

Abstract: Piracatinga (Callophysius macropterus) are a type of bottom feeder catfish encountered in the Amazon River and its tributaries. We report two cases in which human remains were first located based on a characteristic circular distortion of the surface of the river that the Piracatinga make while they feed. Human skin samples of one of the victims recovered from the Piracatinga digestive tract were subjected to mitochondrial DNA analysis that allowed identification of the body of Case 1; the family recognized body parts of Case 2. Importantly, the location of human body parts and their identification based on DNA analysis enabled the respective families to obtain a death certificate expeditiously in the absence of identifiable remains—a process that normally requires 5 years under current Brazilian law, and in the absence of closure, imposes severe emotional stress on the family of the deceased. [ABSTRACT FROM AUTHOR]

Abstract: Motivated by the debate over how to deal with the huge backlog of untested sexual assault kits in the U.S.A., we construct and analyze a mathematical model that predicts the expected number of hits (i.e., a new DNA profile matches a DNA sample in the criminal database) as a function of both the proportion of the backlog that is tested and whether the victim–offender relationship is used to prioritize the kits that are tested. Refining the results in Ref. (Criminol Public Policy, 2016, 15, 555), we use data from Detroit, where government funding was used to process ≈15% of their backlog, to predict that prioritizing stranger kits over nonstranger kits leads to only a small improvement in performance (a 0.034 increase in the normalized area under the curve of the hits vs. proportion of backlog tested curve). Two rough but conservative cost‐benefit analyses—one for testing the entire backlog and a marginal one for testing kits from nonstranger assaults—suggest that testing all sexual assault kits in the backlog is quite cost‐effective: for example, spending ≈$1641 to test a kit averts sexual assaults costing ≈$133,484 on average. [ABSTRACT FROM AUTHOR]

The interpretation of complex DNA profiles is facilitated by a Bayesian approach. This approach requires the development of a pair of propositions: one aligned to the prosecution case and one to the defense case. This note explores the issue of proposition setting in an adversarial environment by a series of examples. A set of guidelines generalize how to formulate propositions when there is a single person of interest and when there are multiple individuals of interest. Additional explanations cover how to handle multiple defense propositions, relatives, and the transition from subsource level to activity level propositions. The propositions depend on case information and the allegations of each of the parties. The prosecution proposition is usually known. The authors suggest that a sensible proposition is selected for the defense that is consistent with their stance, if available, and consistent with a realistic defense if their position is not known. [ABSTRACT FROM AUTHOR]

This article explores the fallout from the decision in S & Marper v. UK (2008), where the European Court of Human Rights ( ECtHR), in ruling that the UK's DNA retention regime breached human rights, was 'struck by the blanket and indiscriminate nature' of the power to retain DNA and stated that the UK government required 'weighty reasons' to justify the retention of DNA in cases of unconvicted individuals. Since the ruling, successive UK governments have drafted new retention regimes but serious doubts remain as to whether the issue of DNA retention has been satisfactorily resolved. [ABSTRACT FROM AUTHOR]

DNA amplification is a fundamental yet costly process used in DNA analysis. This study evaluated half-reaction amplification (12.5, 12, and 13 uL) using the Promega Powerplex® 16 Kit with the hope of reducing sample analysis costs by half. A sensitivity study was completed, along with the testing of various blood stain samples including those with low (<0.40 ng) and high DNA concentrations (>3.0 ng), peak height imbalances, and allelic drop-out. Also, 467 samples submitted to the MUFSC laboratory for testing were analyzed. Results indicate that half-reaction amplification produced higher quality profiles than full-reactions. Average peak heights increased by 85%, peak height imbalances improved, and drop-out was eliminated in 75.8% of samples. Only eight of 467 case samples required re-amplification, a success rate of 94% was observed, and the repeat rate decreased significantly. Finally, a DNA input of 0.25–1.0 ng is ideal for half-reaction amplification. [ABSTRACT FROM AUTHOR]

DNA profiling is a well-established technology for use in the criminal justice system, both in courtrooms and elsewhere. The fact that DNA profiles are based on non-coding DNA and do not reveal details about the physical appearance of an individual has contributed to the acceptability of this type of evidence. Its success in criminal investigation, combined with major innovations in the field of genetics, have contributed to a change of role for this type of evidence. Nowadays DNA evidence is not merely about identification, where trace evidence is compared to a sample taken from a suspect. An ever-growing role is anticipated for DNA profiling as an investigative tool, a technique aimed at generating a suspect where there is none. One of these applications is the inference of visible traits. As this article will show, racial classifications are at the heart of this application. The Netherlands and its legal regulation of ‘externally visible traits’ will serve as an example. It will be shown that, to make this technology work, a large number of actors has to be enrolled and their articulations invited. This indicates that instead of a ‘silent witness’, a DNA profile should rather be seen as an ‘articulate collective’. Based on two cases, I argue that the normativity of visible traits is context-dependent. Taking into account the practices in which technology is put to use alerts us to novel ethical questions raised by their application. [ABSTRACT FROM AUTHOR]

Accurate quantification of DNA samples is an important step in obtaining accurate and reproducible short tandem repeat (STR) profiles. Quantitative real-time-PCR has improved the speed and accuracy of DNA quantification over earlier methods, albeit at significantly greater cost per reaction. Here, the performance of reduced volume (10 μL) DNA quantification assays using the Quantifiler™ Human DNA Quantification Kit was evaluated using commercial standards and single source biological stains (e.g., venous blood, saliva, and semen). In addition, casework-type samples including those subjected to environmental contaminants containing PCR inhibitors and samples having undergone extensive DNA degradation were also quantified. The concentration of DNA in various forensic samples ranged from 0 to 2.9 ng/μL depending on sample source and/or environmental insult. Compared to full-scale reactions, reduced volume assays displayed equivalent to improved amplification efficiency and sample-to-sample reproducibility (±0.01–0.17 CT FAM). Furthermore, the use of data from reduced-scale Quantifiler™ reactions facilitated the accurate determination of the amount of sample DNA extract needed to generate quality STR profiles. The use of 10 μL-scale Quantifiler™ reaction volumes has the practical benefit of increasing the effective number of reactions per kit by 250%; thereby reducing the cost per assay by 60% while consuming less sample. This is particularly advantageous in cases of consumptive testing. [ABSTRACT FROM AUTHOR]

Interpreting mixture short tandem repeat DNA data is often a laborious process, involving trying different genotype combinations mixed at assumed DNA mass proportions, and assessing whether the resultant is supported well by the relative peak-height information of the mixture sample. If a clear pattern of major–minor alleles is apparent, it is feasible to identify the major alleles of each locus and form a composite genotype profile for the major contributor. When alleles are shared between the two contributors, and/or heterozygous peak imbalance is present, it becomes complex and difficult to deduce the profile of the minor contributor. The manual trial and error procedures performed by an analyst in the attempt to resolve mixture samples have been formalized in the least-square deconvolution (LSD) framework reported here for two-person mixtures, with the allele peak height (or area) information as its only input. LSD operates on the peak-data information of each locus separately, independent of all other loci, and finds the best-fit DNA mass proportions and calculates error residual for each possible genotype combination. The LSD mathematical result for all loci is then to be reviewed by a DNA analyst, who will apply a set of heuristic interpretation guidelines in an attempt to form a composite DNA profile for each of the two contributors. Both simulated and forensic peak-height data were used to support this approach. A set of heuristic guidelines is to be used in forming a composite profile for each of the mixture contributors in analyzing the mathematical results of LSD. The heuristic rules involve the checking of consistency of the best-fit mass proportion ratios for the top-ranked genotype combination case among all four- and three-allele loci, and involve assessing the degree of fit of the top-ranked case relative to the fit of the second-ranked case. A different set of guidelines is used in reviewing and analyzing the LSD mathematical results for two-allele loci. Resolution of two-allele loci is performed with less confidence than for four- and three-allele loci. This paper gives a detailed description of the theory of the LSD methodology, discusses its limitations, and the heuristic guidelines in analyzing the LSD mathematical results. A 13-loci sample case study is included. The use of the interpretation guidelines in forming composite profiles for each of the two contributors is illustrated. Application of LSD in this case produced correct resolutions at all loci. Information on obtaining access to the LSD software is also given in the paper. [ABSTRACT FROM AUTHOR]